Answer:
Low - The generation of nitrates (NO 3-) requires oxygen, so the oxygen levels will be low
Explanation:
Nitrates are formed when the ammonia react with oxygen present in water. The oxygen which react with ammonia is not the oxygen of water molecule, it is the dissolved oxygen. This oxygen is used by aquatic animals for breathing. If nitrates are formed so the concentration of dissolved oxygen will be lowered which causes suffocation and bad impact on marine organisms and the whole ecosystem will be disturbed.
The answer is NO. This is because different environments require different adaptations. A desirable trait in one environment may be inconsequential or detrimental in another environment. This is the reason also why evolution is continuous as natural selection acts on traits of a population to ensure desirable traits are retained with changes in the environment in a dynamic world.
Answer:

Explanation:
The distance to the Sun is 5,890,000,000,000. We need to write this distance in km.
A number can be written as
in scientific notation where x is a real no and y is any integer.
There are 10 zeros in the given number and also there are 12 digits after. It would mean that,

So, the distance in scientific notation is : 
Since nicotine is a form of a stimulant drug, in cigarette smoke it can cause addiction.
Many people who smoke are actually addicted to smoking, and cannot stop doing so easily, which is similar to how drug addicts behave when it comes to using drugs.
Blood cells is the answer